White Bladderpod (Physaria pallida)

White bladderpod is an erect to spreading annual in the mustard family. Plants range from 2 to 25 inches tall. The leaves are alternate, yellowish green to grayish green, slightly hairy, linear to oblong in shape, with smooth, toothed or sometimes wavy margins. Leaves near the plant base are deeply lobed and up to 4 inches long and 3/4 inch wide, becoming smaller toward the top of the plant. Flowers are white with yellow bases. They have 4 egg-shaped petals about 1/2 inch long and 3/8 inch wide. Small plants may have a single flower on a short stalk, while larger plants may have up to 24 flowers along an elongated stem up to 6 inches in length. The round fruits, about 1/4 inch in diameter, produce 8-12 tiny, flattened seeds.

Life History

After its initial discovery in 1830, white bladderpod escaped detection again until 1981, when it was rediscovered by botanists searching for a different rare species. White bladderpod flowers during April and May and the species reproduces by seed. Little is known concerning the pollination, seed dispersal, seed biology, or seedling survival. It is found on shallow, seasonally wet, alkaline soils, which differ from the sandy, acidic soils usually found in east Texas. The unique soil conditions support open, herbaceous, specialized plant communities. Plant species associated with white bladderpod include Drummond onion, Drummond sandwort, western daisy, groovestem, Indian plantain, yellow sweet-clover, canary grass, Ozark savory, and beaked cornsalad.

Habitat

White bladderpod occurs in grassy openings, or on the open edges, of oak-hickory-pine woodlands of east Texas on seasonally wet, non-acidic soils.

Distribution

There are 9 known populations of white bladderpod, all of them in San Augustine county. This species is known from only a few sites in the county. It is restricted to the Weches formation, a geologic formation composed of glauconite. One site was destroyed by mining the glauconite for use as a road base.

Other

White bladderpod was listed as endangered by the U.S. Fish and Wildlife Service in March 1987. Landowners can help conservation efforts by learning to recognize this rare plant and protecting the areas where it grows from land use changes. Maintaining native herbaceous vegetation on these sites is important. Removing woody vegetation, either mechanically or by use of prescribed fire under controlled conditions, can help maintain open grassland habitat suitable for white bladderpod. Herbicide use should be carefully planned and highly selective to target species to avoid impacts on white bladderpod. Brush management work, prescribed burning, and use of herbicides should be limited to the July-October non-flowering period as much as possible. During logging activity, damage to these sites by large vehicles and alteration of surface hydrology should be avoided if possible.